Four groups of flavouring agents were evaluated by the Procedure for the Safety Evaluation of Flavouring Agents outlined in Figure 1 (Annex 1, references 116, 122, and 131).

The Committee noted that in applying the Procedure, the substance is first assigned to one of the structural classes identified at the forty-sixth meeting of the Committee (Annex 1, reference 122):

Class I. Substances that have simple chemical structures and efficient modes of metabolism that would suggest a low order of toxicity when given by the oral route

Class II. Substances that have structural features that are less innocuous than those of substances in Class I but are not suggestive of toxicity. Substances in this class may contain reactive functional groups.

Class III. Substances that have structural features that permit no strong initial presumption of safety or may even suggest significant toxicity.

A key element of the Procedure involves determining whether a flavouring agent and the product(s) of its metabolism are innocuous and/or endogenous. For the purposes of evaluation, the Committee used the following definitions, adapted from the report of its forty-sixth meeting:

Innocuous metabolic products are defined as products that are known or readily predicted to be harmless to humans at the estimated intake of the flavouring agent.

Endogenous substances are intermediary metabolites normally present in human tissues and fluids, whether free or conjugated; hormones and other substances with biochemical or physiological regulatory functions are not included. The estimated intake of a flavouring agent that is, or is metabolized to, an endogenous substance should not give rise to perturbations outside the physiological range.


Intakes were estimated from surveys carried out in Europe and the United States. Estimates of the intake of flavouring agents by populations typically involve the acquisition of data on the amounts used in food. In Europe, a survey was conducted in 1995 by the International Organization of the Flavor Industry, in which flavour manufacturers reported the total amount of each flavouring agent incorporated into food sold in the European Union during the previous year. Manufacturers were requested to exclude use of flavouring agents in pharmaceutical, tobacco, and cosmetic products. In the United States, a series of surveys was conducted between 1970 and 1987 by the National Academy of Sciences National Research Council (under contract to the Food and Drug Administration) in which information was obtained from ingredient manufacturers and food processers on the amount of each substance destined for addition to the food supply and on the usual and maximal levels at which each substance was added to a number of broad food categories.

In using data from these surveys to estimate the intakes of flavouring agents, it was assumed that only 60% of the total amount used is reportedin Europe and 80% of the amount used is reported in the USA and that the total amount used in food is consumed by only 10% of the population.


The population of consumers was assumed to be 32 106 in Europe and 24 106 in the United States.

Figure 1

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       Toxicological Abbreviations